7y4i

Structural highlights

Function

SPY_ARATH Probable O-linked N-acetylglucosamine transferase (OGT) involved in various processes such as gibberellin (GA) signaling pathway and circadian clock. OGTs catalyze the addition of nucleotide-activated sugars directly onto the polypeptide through O-glycosidic linkage with the hydroxyl of serine or threonine. Probably acts by adding O-linked sugars to yet unknown proteins. Acts as a repressor of GA signaling pathway to inhibit hypocotyl elongation. Functions with GIGANTEA (GI) in pathways controlling flowering, circadian cotyledon movements and hypocotyl elongation. Acts as a light-regulated promoter of elongation via its interaction with GI. Acts as an activator of cytokinin signaling. Required with SEC for gamete and seed development (PubMed:12136030). Its OGT activity has been proved in vitro but not in vivo (Ref.5, PubMed:11457967, PubMed:12136030, PubMed:15155885, PubMed:15608330, PubMed:8799194). Possesses O-fucosyltransferase activity on specific serine and threonine residues (PubMed:28244988). Mediates O-fucosylation of the DELLA protein RGA, a repressor of the GA signaling pathway (PubMed:28244988). O-fucosylation enhances RGA activity by promoting RGA binding to key transcription factors in brassinosteroid and light-signaling pathways (PubMed:28244988). Regulates root hair patterning upstream of the transcription factor WER, independently of DELLA proteins and GA signaling (PubMed:32928908). Involved in abscisic acid (ABA) signaling partly through functional ABAR (PubMed:34712252). Mediates O-fucosylation of CPN20 that may depress ABA responses during seed germination and seedling development (PubMed:34712252). Involved in the modulation of the pace of the circadian clock by mediating O-fucosylation of APRR5, one of the core circadian clock components (PubMed:31899321). O-fucosylation promotes APRR5 proteolysis (PubMed:31899321).^{[1] [2] [3] [4] [5] [6] [7] [8] [9] [10]}

References

1. ↑ Swain SM, Tseng TS, Olszewski NE. Altered expression of SPINDLY affects gibberellin response and plant development. Plant Physiol. 2001 Jul;126(3):1174-85. PMID:11457967
2. ↑ Hartweck LM, Scott CL, Olszewski NE. Two O-linked N-acetylglucosamine transferase genes of Arabidopsis thaliana L. Heynh. have overlapping functions necessary for gamete and seed development. Genetics. 2002 Jul;161(3):1279-91. PMID:12136030
3. ↑ Tseng TS, Salome PA, McClung CR, Olszewski NE. SPINDLY and GIGANTEA interact and act in Arabidopsis thaliana pathways involved in light responses, flowering, and rhythms in cotyledon movements. Plant Cell. 2004 Jun;16(6):1550-63. Epub 2004 May 21. PMID:15155885 doi:http://dx.doi.org/10.1105/tpc.019224
4. ↑ Greenboim-Wainberg Y, Maymon I, Borochov R, Alvarez J, Olszewski N, Ori N, Eshed Y, Weiss D. Cross talk between gibberellin and cytokinin: the Arabidopsis GA response inhibitor SPINDLY plays a positive role in cytokinin signaling. Plant Cell. 2005 Jan;17(1):92-102. Epub 2004 Dec 17. PMID:15608330 doi:http://dx.doi.org/tpc.104.028472
5. ↑ Zentella R, Sui N, Barnhill B, Hsieh WP, Hu J, Shabanowitz J, Boyce M, Olszewski NE, Zhou P, Hunt DF, Sun TP. The Arabidopsis O-fucosyltransferase SPINDLY activates nuclear growth repressor DELLA. Nat Chem Biol. 2017 May;13(5):479-485. doi: 10.1038/nchembio.2320. Epub 2017 Feb , 28. PMID:28244988 doi:http://dx.doi.org/10.1038/nchembio.2320
6. ↑ Wang Y, He Y, Su C, Zentella R, Sun TP, Wang L. Nuclear Localized O-Fucosyltransferase SPY Facilitates PRR5 Proteolysis to Fine-Tune the Pace of Arabidopsis Circadian Clock. Mol Plant. 2020 Mar 2;13(3):446-458. doi: 10.1016/j.molp.2019.12.013. Epub 2019 , Dec 31. PMID:31899321 doi:http://dx.doi.org/10.1016/j.molp.2019.12.013
7. ↑ Mutanwad KV, Zangl I, Lucyshyn D. The Arabidopsis O-fucosyltransferase SPINDLY regulates root hair patterning independently of gibberellin signaling. Development. 2020 Oct 9;147(19):dev192039. doi: 10.1242/dev.192039. PMID:32928908 doi:http://dx.doi.org/10.1242/dev.192039
8. ↑ Liang L, Wang Q, Song Z, Wu Y, Liang Q, Wang Q, Yang J, Bi Y, Zhou W, Fan LM. O-fucosylation of CPN20 by SPINDLY Derepresses Abscisic Acid Signaling During Seed Germination and Seedling Development. Front Plant Sci. 2021 Oct 12;12:724144. doi: 10.3389/fpls.2021.724144. , eCollection 2021. PMID:34712252 doi:http://dx.doi.org/10.3389/fpls.2021.724144
9. ↑ Jacobsen SE, Binkowski KA, Olszewski NE. SPINDLY, a tetratricopeptide repeat protein involved in gibberellin signal transduction in Arabidopsis. Proc Natl Acad Sci U S A. 1996 Aug 20;93(17):9292-6. PMID:8799194
10. ↑ Hartweck LM, Scott CL, Olszewski NE. Two O-linked N-acetylglucosamine transferase genes of Arabidopsis thaliana L. Heynh. have overlapping functions necessary for gamete and seed development. Genetics. 2002 Jul;161(3):1279-91. PMID:12136030